PTL 1 discloses a system which executes processing of suspending the use of a credit card fraudulently used in purchasing commodities or services. In the processing of suspending the use, information written in the card is partially destroyed, wrong information is written in the card, and a flag indicating the unavailability (invalidity) of the card is set for the card.
A host computer of this system first outputs information including a blacklist of credit cards of credit company members as card information. The blacklist means a list of invalid cards. A terminal computer of each affiliated store receives and stores the information and executes processing of suspending the use of a credit card input to a card reader when the card is on the blacklist.
In this system, the host computer regularly or irregularly transmits the information of all card members. When any affiliated store has basic card information, only information obtained when the credit card has changed from “valid” to “invalid” or from “invalid” to “valid” is transmitted to update the basic information in the affiliated store.